#include<iostream>
#include<cmath>
#include<algorithm>
using namespace std;
int main(){
    int m,n;
    cin>>m>>n;
    int a[100010],b[100010];
    for(int i=1;i<=m;i++) cin>>a[i];
    for(int i=1;i<=n;i++) cin>>b[i];
    int sum=0;
    sort(a+1,a+m+1);
    for(int i=1;i<=n;i++){
        int l=0,r=m+1;
        while(l<r){
            int mid=(l+r)/2;
            if(a[mid]<=b[i]){
                l=mid+1;
            }
            else r=mid;
        }
        if(b[i]<a[1]+1){
            sum+=a[1]-b[i];
        }
        else sum+=min(abs(a[l-1]-b[i]),abs(a[l]-b[i]));
    }
    cout<<sum;
}